PROTECTIVE SHIELD

The present invention, relates to ' dëé^l ate- êcfans^- .; sécuirité and, more particularly to optical displays ballistic protection such as glazing for buildings and vehicles, protective screen in the event of a riot, shields for the head and to secure panels ( clipboards ).

A need exists for optical displays security could be manufactured as a single piece to the desired shape without ilsoit necessary to laminating several layers together.

The aim of the present invention is to provide a method for producing security screens and 1' corresponding safety equipment.

The aim and advantages of the present invention will be more easily understood with reference to the attached drawing wherein:

figure I is a perspective view of a panel to be fixed, and

figure 2 is a perspective view of a windshield for motor vehicle.

By referring more particularly to Figure L, the reference 10 represents the base member, of the panel to be fixed by a fastener (or clip) 11 secured to the top of 1' base element by means of devices 12 or other appropriate attachment means. The panel to be fixed, comprising a base member-type ballistic. polyurethane can be used not only as display holder or paper but also as a screen protector for protecting a police officer in patrol or any other peace officer against a shot when it approaches of a marksman in a car to 1' stop. The panel to be fixed preferably has a épaisd' about 6.35 to 19.05 mm and a length and a width suitable.

In referring to Figure 2, a windshield 13 in a frame which is mounted on a motorcycle by means of mounting bracket 14 and the windshield has an optical transparency and ballistic resistance sufficient to serve as a baffle when the windscreen receives a ball of a firearm.

The optical panel according to the present invention can have any length and any appropriate width but the thickness is in a certain measure based on the projectile to stop. For example, it has been found that a thickness of between and 6.35 19.05 mm is satisfactory for windshields, side windows, of automobile rear windows, face shields and screens-. riot, -for ' fftentionnèr' seulentent few-' security screens.

Polyurethanes useful for making 1' element the écran.de. cadre are transparent with excellent optical transparency and excellent ballistic properties.

Optically transparent The polyurethane of the present invention can be prepared by reacting one equivalent of a polyester glycol or a polyether glycol having a molecular weight of about 700 to 1000 with methylene bis (cyclohexyl isocyanate) to achieve an equivalent ratio of about 3 NCO to OH 1, the range being between 2.7 and I 4.5 NCO to OH. The prepolymer is then brought TO react with 4.4 '-methylene bis (2-chloroaniline) to achieve an equivalent ratio of 0.90 to 1.04 NH₂ / 1,0 NCO, the preferred range being between 0_r 9 and 0.99 NH₂ / 1,0 NCO.

Glycols that may be used for preparing the compositions of the present invention include polyoxyalkylene ether glycols and polyester glycols. The glycpls have a number-average molecular weight between about 700 and 1000. Are particularly effective for the production of polyurethanes high quality, glycols having molecular weights between about 750 and 900.

Illustrative examples of polyoxyalkylene ether glycols include poly -1,2-propylene ether glycol, poly -1,3-propylene ether glycol and polytetramethylene ether glycol. The polyoxyalkylene ether glycols for use in the present invention can be prepared by condensing epoxides or other cyclic ethers as it is well known in the art.

Representative polyesters for use in the present invention include polycaprolactones, and polyesters from the esterification of dicarboxylic acids of 4 to 10 carbon atoms, such as acids ordifique, succinic and sebacic, by low molecular weight glycols of 2 to 8 carbon atoms such as ethylene glycol, propylene glycol, the glycol diëthylène, the 1,4-butane diol and-the 1-6 hexane diol. The polycaprolactones are prepared by condensing caprolactone in the presence of compounds.

bifunctional. active hydrogen such as water or glycols to molecular baspoids above mentioned. Polyesters obtained by esterification of carboxylic acids by glycols can be synthesized by known methods of esterification or trarts -is êx ific -ation " Lesuproduits preferred for the p ^ esenfca raventâo ®, çeofeles |" aîÿçap3r & level i- aett, € ïResè" glygoîs dg Z S iCf atoms: dfe. earbone.

The isocyanates used in the preparation of the cqmpositions of the present invention are preferably diîsocyanatodicyclohexylmêthanes and mixtures thereof containing from about ÎO to 100% of the trans-trans isomer of the 4.4 '- mêthylënebis (cyclohexyl isocyanate}, , which will be hereinafter also called "PICM". Other components commonly present in mixtures of positional isomers or stereoisomers of diisocyanato-dicyclo hexylméthane used in the present invention are the isomers cis-trans and cis-cis the PICM and stereoisomers of 2.4¹ - mêthylënebis -(cyclohexyl isocyanate. The latter products, as well as the trans-trans isomer of PICM, are present in amounts which can be adjusted by the methods used in the preparation of the diisocyanatodicyclohexylmêthane. The diisocyanates preferred are mixtures of isomers of PICM which are liquid at 25 °C at least. Such liquid blend PICM contain less than about 26% of trans-trans isomer and less than about 72% of cis-cis isomer. a particularly preferred mixture contains the trans-trans isomers and cis-cis the PICM in a weight ratio of about 20:65:15 and alternatively contains small amounts, up to about 5% by weight, of 2.4 '- mêthylënebis (cyclohexyl isocyanate). Créférés These mixtures can be easily handled and provide polyurethanes of any quality.

The PICM used in the present invention is prepared

by reaction of phosgene with the 4.4 '- mêthylënebis (cyclohexylamine) corresponding (PACM) according to methods well known in the art, and described in the United States of America patents no. 2,644 007, and 2,680 127 2,908 703. Mixtures of isomers of PACM which by reaction with phosgene, provide a PICM which is liquid at room temperature are also well known in the art, and can be obtained by hydrogenation of the mëthylënedianiline under mild conditions and/or by ' fractional crystallization mixtures of isomers of the PACM in the presence of water and alcohols such as methanol and 1¹ ethanol.

The amine curing agents used in the present invention have only primary amine groups " The amines, preferred are characterized by the presence in their molecules a methylene bridge between two aromatic rings such as as soon wagging & ax. * diffèrentgar plüSsyrîte: lastthstiitueierr ssrr1er noyaur those Se *. ec the series Se. benzidine that differ by only, , let from substitution on the core, the preferred amine being the 4.4: '- methytënehis (2-chloroaniline).

Ort can prepare the polymers of the present, invention-a stage aquasi prëpolymëre or prëpolymëre total, all of which methods are well known in the art. The polymer of the invention may be cast, compression molded, extruded or injection molded. For portions d ' security screen optical, casting is the preferred method.

Polymers that 1 'is preferred for manufacturing security screens are prepared from' £- caprolactose /diacrylate having a molecular weight of about 850 and 4.4 '- mëthylènebis (cyclohexyl isocyanate) containing about 20% of trans-trans isomer, cis-trans isomer 65% and 15% of cis-cis isomer of PICM. The ratio of NCO to OH groups is about 3,0/1,O.

The following non-limiting examples are demonstrative of the invention. In these examples all parts are expressed in equivalent weight or percentages by weight unless otherwise specified.

Example 1.

4.4 A 396 parts '- mëthylènebis PICM (cyclohexyl isocyanate),

425 is added parts of polyester d ' £-caprolactone diacrylate. The mixture is stirred under a nitrogen stream and heated to 96 °C sec, temperature at which the heat source is removed. Is maintained 1' exothermicitë at a temperature below about 116 °C. The pre- 'polymer is then reacted with the 4.4' - mëthylènebis (2-chloroaniline) in a ratio of 1.0 to 0.98 NCO group group

and is cast between two glass plates coated with a release agent diméthyïdichlorosilane as; is carried out in this way the base member of a panel to be fixed of 1,016 x 30,5 x 30,5 cm dimension, then cures at 135 °C for nine hours. The polymer has the following properties t

' Flammability ( FèderalTest does not burn

Method No. 404, Procedure 2021)

Four holes is drilled in the base member of the panel and riveted to secure a fastener or clip 1' base member to provide a panel to be fixed. The panel is satisfactory for use by the police and could be used as a monitor ballistic at a stationary car or other vehicle.

Example [...]

Formulate the example I is added 2% of Tinuvin 328 (UV absorber of benzotriazole) based on the weight of prêpolymère, is cast. and hardens in the same manner. Hardened polymer has the following properties:

têes by the accelerated aging test by exposure or by aging to 1' outside. The 1,016 x 30,5 x 30,5 cm samples are subjected to the ballistic test using bales of "long 22 caliber", high-rate weight of 2.59 grams pulled by a gun and shielded metal balls of a size 0.45 weight of 14.9 grams from a gun model semiautomatic "colt 45". The specimen to be examined is fixed to the frame of test; is pulled samples at an angle of 90° at a distance of 0.61 meter, a bale of "45" followed by five "22" balls to 23.9 °C and to 37.8 °C. The sample is the test successfully because there is neither entry and crack in the sample examined.